Method of making lightweight cylinders



April 1942- s. E. ALLEN 2,279,726

METHOD OF MAKING LIGHTWEIGHT CYLINDERS Filed 001:. 26, 1939 INVENTOR SCOTT EALLEN I TTORNEY Patented Apr. 14, 1942 CYLINDERS Scott E. Allen, Verona, N. J., assignor to C O-Two Fire Equipment Company, Newark, N. J., a corporation of Delaware Application October 26, 1939, Serial No. 301,350

3 Claims.

This invention relates to lightweight high pressure cylinders or containers and the method of making the same.

Heretofore containers have been formed as cylinders open at one end and closed at the other, from plates or billets by successive drawing operations, the cylinders being subsequently (eras-148.2)

Fig. 2 shows the end of the blank closed-in to form the base of the container; and

closed-in or shaped at the open end to receive the coupling of a delivery pipe or nozzle. Containers also have been formed from an openended cylindrical blank in which one end was closed-in to form the bottom or base and the other to form the neck and shoulder of the container. In both of these methods the thickness of the wall of the closed-in end or ends was much greater than necessary to withstand a predetermined high pressure. with the result that these containers were unnecessarily heavy for certain uses. The central or welded portion was found to be non-homogeneous and to develop leaks under pressure. To overcome this, the central portion was drilled out and filled by a plug. It has also been proposed to remove metal either from the exterior and from both the exterior and interior surfaces of the closed end wall to reduce the weight of the cylinder, leaving the metal on the exterior at the central portion of the closed Fig. 3 shows the finished container. In Fig. 1 I have disclosed in longitudinal section one end' oi a cylindrical blank 5, the other end of which may be a continuation of a cylin-- der or may be provided with a shoulder and neck formed in any suitable manner. my method, the end of the blank 5 is spun shut or turned inwardly by any known method producing the construction shown in Fig. 2 inwhich the wall 6 of the body of the container is of the same thickness as the wallof the blank 5 and in which the wall of tha base 1 is of much greater thickness, the wall thickness of the base lbeing much greater than necessary to withstandthe pressure for which the container is made. In

spinning in the end of the container as is known, the ends of the blank are welded or fused together at the center of the closed end as indicated at 8 at which point, however, the material 7 may be traversed by pipes or valleys and may leak at this point or leaks may develop later. I therefore propose to remove the material at this point in the base of the container by drilling as indicated by the representation of a drill 9 in Fig.2. After this has been done and in case the end untouched resulting in a projection or boss on the outer side of the closed end of the container. This, of course, is objectionable in that the length of the containers is increased by the length of the projection and this projection also interferes with resting the containeron its closed end and impacts against it may injure the close end ofthe container.

Therefore, it is an object of my invention to provide a lightweight high pressure container in which the closed end or base of the container is Y of minimum wall thickness required to withstand a predetermined high pressure and one in which the increase of wall thickness necessary to support a closure plug occurs on the inner face of the base of the container thus providing a shorter container and one in which the outer face of the base is smooth and does not present any projecting boss interfering with resting the container on its base or which might receive impactsdisrupting the container.

Other objects of the invention will appear from the following description, taken in connection with the drawing, in which'- Fig. 1 is a longitudinal section of a part of a cylindrical blank from whichv a container may be formed;

container is closed-in at the other end, a suitable machining tool, not disclosed but well known, may be inserted through the opening produced by the drill and metal removed from the inside face of the end of the container. The amount of material and the area in which the material is removed is indicated at IU, Fig. 3, leaving the end wall or base ll of the same, or, if desired, less thickness than that of the-blank 5. As shown of the container are made relative'y thin, it is necessary to provide the same with a boss I2 in order that there'may be sufficient anchorage for the plug which is to be secured therein and suificient length of thread to prevent leakage. The

container so formed has the necessary strength and is of as light weight as possible, is leakproof, has an exterior smooth base, and is of a minimum length, constituting advantages which were not possible with the methods heretofore use'd.'

While I have disclosed one method of manufacturing containers and disclosed one form of container made by this method, it is to be undera stood that I reserve the right to all such changes In carrying out- I as come within the principles of my invention and the scope of the appended claims.

I claim:

1. The method of producing a high pressure cylindrical thin walled metal container from a tube open at at least one end, ,which comprises closing-in an open end of the tube by a spinning, operation producing, an end wall of greater thickness than the side wall of the container, drilling an orifice through said end wall axially of said' container, and machining excess thickness oi metal from an annular zone on the inner face of the end wall surrounding said oriflce and spaced from the axis of said container at greater radial distance than the length of the radius of said closing-in an open end of the tube by a spinning operation producing an end wall of greater thickness than the side wall ofthe container, drilling an orifice through said end wall of said container, machining excess thickness of metal from an annular zone on the i'ace oi the end wall surrounding said orifice and spaced from the axis of the container at greater radial distance than the length of the radius oi. said oriiice, and securing a plug in said orifice.

3. The method oi producing ,a high pressure cylindrical thin walled metal container from a tube open at'at least one end, which comprises closing-in an open end of the tube by a spinning operation producing an end wall oi greater thickness than the side wall of .the container, drilling an orifice through said end wa axially of said container, machining excess t ckness of metal from an annular zone on the inner iace oi the end wall surrounding said oriilce and spaced from the axis of the container at a greater radial distance than the length of the radius of said orifice, and providing the wall of said orifice with a screw thread. 7 

